Traction Axle Inverter Groups for Reduced Steering Radius

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Solution Overview

Problem

Current traction axles for self-propelling work machines, such as lift trucks, face limitations in maneuvering capacity in small spaces due to the fixed rotation center outside the wheel group, restricting the minimum steering radius and making it difficult to navigate tight areas effectively.

Innovation Solution

The traction axle incorporates inverter groups on semi-axes driven by a steering column, allowing the wheel groups to rotate in opposite directions, with the rotation center shifting internally based on the steering angle, facilitated by clutches, brake-clutches, and couplers, enabling the vehicle to rotate around its vertical axis and minimize steering space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional differential axle configuration is used, then the structure is simple and reliable, but the steering radius is large and maneuverability in small spaces is poor

Engineering Contradiction:
ImprovemaneuverabilityVSAvoidaxle structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The axle is divided into two independent drive units, each with its own differential mechanism and wheel group. This segmentation allows each side to operate independently with opposite rotation directions, enabling the vehicle to rotate around its vertical axis and achieve minimal steering radius for improved maneuverability in confined spaces

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention inverts the traditional differential operation by making the two wheel groups rotate in opposite directions rather than the same direction. This inversion is achieved through independent differentials on each side, allowing one wheel group to rotate forward while the other rotates backward, creating a pivot point at the vehicle center for maximum maneuverability

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If inverter groups are added to enable opposite rotation, then the steering radius is minimized, but the device complexity increases

Engineering Contradiction:
Improvesteering capabilityVSAvoidinverter and clutch mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The differential mechanisms serve multiple functions: they provide both the speed differentiation needed for steering and the opposite rotation capability for minimal radius turning. The clutch mechanisms similarly serve dual purposes of engaging/disengaging the inverter groups and controlling the torque distribution, reducing the need for separate control systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The inverter groups act as intermediaries between the power source and the wheel groups, converting the rotation direction without requiring direct mechanical connection changes. The clutch mechanisms serve as intermediaries to smoothly engage and disengage the inverter groups, protecting the system from shock loads while enabling flexible steering control

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If wheel groups rotate in opposite directions, then the rotation center moves internally improving steering, but the control system becomes more complex

Engineering Contradiction:
Improvesteering precisionVSAvoidcontrol system automation
Core Design Contradiction:
Ease of operationVSExtent of automation

Solution Approach 1:

The control system incorporates feedback from steering angle sensors and wheel rotation sensors to automatically adjust the clutch engagement and inverter operation. This feedback mechanism ensures precise control of the opposite rotation, maintaining the rotation center within the desired internal position while compensating for load variations and steering dynamics

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2535308B1A traction axle for work machines.
Publication Date: 2016.02.03 FIVES OTO
  • EP2535308B1 patent drawingFigure 1~2
  • EP2535308B1 patent drawingFigure 3~4
  • EP2535308B1 patent drawingFigure 5~6

AI summary

A traction axle (20), in particular for self-propelling work machines, in particular lift trucks usable for sorting containers and generic goods, comprises, on two semi-axles (23, 24) in output from a differential (21), motion inverter groups (29, 30) commanded directly by a steering column of the vehicle, or as a function of a requested steering angle, such as also to cause, if required, rotation of the two wheels (25, 26) of the axle in opposite directions. This offers the possibility of bringing the rotation centre of the vehicle internally of a base area of the vehicle itself, and thus obtaining a substantial reduction of the steering space in comparison to the space required in traditional work machines.